Expansible piston.



E. VAN BEVER.

BXPANSIBLE PISTON.

APPLIoATIoN FILED 5111111.18, 1911.

1,031,212. Patented July 2,1912.

I I I I l I I I I I I l I I l EDMOND VAN BEVER, 0F WATERTOWN, MASSACHUSETTS.

EXPANSIBLE PISTON.

Specification of Letters Patent.

Application filed September 18, 1911.

Patented July 2, 1912. Serial No. 649,889.

To all 'whom it may concern:

Be it known that I, EDMOND VAN BEVER, a citizen of the United States, and resident of`Watertown, county of Middlesex, Commonwealth of Massachusetts, have invented an Improvement in Expansible Pistons, ot' which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to pistons and, while applicable to other and more general uses, is especially designed .for use in gas engine construction.

As is Well known, the ordinary engine piston or plunger, though it may have been originally formed to closely fit its cylinder, after a period of use wears down to a certain extent and this, along with the wear of the cylinder, makes the piston a loose fit,

in the cylinder so that it tends to have some small lateral chucking playtherein, which is only imperfectly prevented by the packings. This looseness of the piston in its cylinder tends to the premature destruction of the packing rings, as well as requiring special attention to the fitting of these.

The present construction provides a piston formed so as to be expansible from within to take up for the small diminution in its diameter due to wear, so that, even after a considerable period of use, its peripheral dimension may be the same as at the beginning.

The invention will be better understood from the following detailed description taken in connection with the accompanying drawings and will thereafter be pointed out in the appended claims.

Referring. to the drawings, Figure 1 is a central longitudinal section showing a piston wherein my invention is carried out, a

. portion of the cylinder being shown broken away. Fig. 2 isa transverse section taken pt the right of Fig. 1, portions of the pison being shown in elevation. Fig. 3 is a detail section on line 3-3 of Fig. 2. Fig. 4 is a fragmentary sectional detail showing another form of expanding mechanism, and Fig. 5 is a section on line 5 5 of Fig. 4.

The piston 10, usually of cast iron, is shown as of the integral hollow shell type with its outer end closed and is fitted to the cylinder 11 and united to a connecting rodl2 by wrist pin 13 fitted to sockets in bosses 14 projecting inward from the hollow shell intermediate of its length. The hollow shell of the piston, as is usual, extends rea-rwardly for some distance from the wrist pin connect-ion as seen at 15, this rearwardly extending portion being slightly tapered so as to terminate in a relatively thin inner extremity. In the practice of my invention this hollow shell, for a considerable distance from its inner end, is divided into a number of sections, shown as four, by lengthwise slits 16. These slits, which, in the illustrative embodiment shown, extend substantially to the wrist pin connection, though the exact length thereof is not material, may be readily formed by sawing the piston shell with an ordinary metal saw. These sectional portions have a certain amount of springing capacity which need only be very slight for the present purpose, and as a means for expanding them outward to the small extent necessary, I provide an expanding ring 17 fitted into the piston sleeve and held from casual displacement by means shown as a screw bolt 18 tapped in a hole partly in the ring and partly in the piston shell. The ring 17 is divided at the point 19 and the abutting ends at this point are adapted to be forced apart by a screw bolt 20 fitted to a hole formed in the abutting ends, this-bolt having a conical head 21 and having fitted thereto a nut 22 with a conical head 23. Thus as the nut 22 is screwed up on the bolt 20, the conical portions 21, 23 force the abutting ring ends apart, causing expansion .of the r-ing and correspondingv expansion of the sectional portions of the piston shell. As a means for preventing casual displacement of the nut 22, it is formed with an abutment plate 24 flattened ofi", as seen at 25 to lit the inside of the piston shell. The screw bolt 20 is likewise prevented from casual displacement after adjustment by having a cotter pin 26 passed through a transverse aperture in its end with its extremity in position to press against the inside of the piston shell, so that both the screw bolt and its nut are thus held against movement, and any desired expanding adjustment of the piston once effected is reliably maintained.

The form of expanding mechanism just described is especially applicable for equipping worn pistons with my invention, since it does not require an machining of the piston. In the case o new pistons whlch can be conveniently machined the expanding device of Fig. 4 and Fig. 5 may be advantageously employed. As shown in these figures, the inner end 15 of the piston, which is provided with slots 16 as before described, has an internal.- tapered thread formed" therein as seen at 28, and engaging with this thread is a ring 17 having a correspondingly tapered and threaded outer periphery. This ring may be screwed into the piston end to expand the sectional portions thereof to the extent desired, and as a` suitable means for preventing the working out of this ring, I provide radial holes 29 therethrough at intervals through one or more of which a Cotter pin' 30 is passed so that its head extends up into a slot 16 Without reaching the periphery of the piston, while its inwardly projecting ends may be bent over the ring'to prevent dislodgment. Thus the head of the Cotter pin engaging with the walls of the slot 16 effectively prevents any turning of the ring and holds the parts in precise adjusted position. The resiliency effected by the slits 16 may be somewhat enhanced if desired by the drilling of holes 27 in the extremities .of these slits, though this is not essential to the effecbe carried out with various tive carrying out of the invention.

It will be understood that while a cast iron piston of usual form is shown for illustrative purposes in setting forth the principles of my invention, the invention is not limited to this one form of piston, but may different piston and plunger constructions. The invention is likewise adapted for use in the production of new pistons or and worn plungers. ger worn by use, all that is necessary is to remove it, saw he slits 16 from its inner end, select` an expanding ring of proper size, and fit it to the inside of the shell, this fitting being facilitated by the usual tapering form of the standard types of hollow shell piston from the wrist pininward. j

Having described my invention, what I claim as newl and desire to secure by Let-ters Patent is:

1; A piston formed with a hollow shell integral with the main body thereof,there being slits lengthwise through the shell from its inner end, and means for expanding the sectional portions thus formed to take up for wear.

2. A piston formed -with a hollow shell integral with the main body thereof, there being a plurality of equally spaced apart for the refitting of oldV In the case of a plunlits inner end, and means 'lengthwise slits through the inner end portion of the shell, and an internal expander for the sectional shell portions thus formed.

3. A piston, having an inwardly extending shell portion integral therewith with a plurality of equally spaced apart lengthwise extending slits therethrough, and an internal expander for springlng out and holding in expanded adjustment the sectional shell portions thus formed.

et. A piston, having a wrist pin fitted to inwardly projecting bosses thereof, and a shell portion extending inwardly from said wrist pin integral with the body of the piston, said shell portion being sectioned by a plurality of equally spaced apart slits into segmental portions, ing ring fitted to the interior of said sectional shell portions.

5. A hollow shell piston, extending bosses with \a wrist pin fitted therein, and a shell portion integral with the pisto-n body extending inwardly from said wrist pin, said integral shell portion having a lengthwise extending slit therethrough, and an interna-l expander fit-ted to expand said inwardly extending shell portion.

6. A piston, comprising an integral hollow shell portion with a slot extending lengthwise therethrough for a part of its length, and means for expanding said shell portion to take up for wear.

7. An integral hollow shell piston, having slits lengthwise through the shell from its inner end, and means for expanding the sectional portions thus formed to take up wear, said means consisting in a tapered threaded ring fitted to a tapered threaded seat in the end of the piston.

^ 8. An integral hollow shell piston, having slits lengthwise through the shell from for expanding the sectional portions thus formed to take up wear, said means consisting in a tapered threaded ring fitted to a ,tapered threaded seat in the end of the piston, said ring having a radially extending hole therethrough with a pin passed through said hole and engaging with the walls of one of said slits.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

EDMOND VAN BEVER.

Witnesses:

CLYDE L. Roenes, EDWARD MAXWELL.

having inwardly 

